src/librustc_trait_selection/traits/query/type_op/implied_outlives_bounds.rs

   1 use crate::infer::canonical::{Canonicalized, CanonicalizedQueryResponse};
   2 use crate::traits::query::outlives_bounds::OutlivesBound;
   3 use crate::traits::query::Fallible;
   4 use rustc_middle::ty::{ParamEnvAnd, Ty, TyCtxt};
   5
   6 #[derive(Clone, Debug, HashStable, TypeFoldable, Lift)]
   7 pub struct ImpliedOutlivesBounds<'tcx> {
   8     pub ty: Ty<'tcx>,
   9 }
  10
  11 impl<'tcx> ImpliedOutlivesBounds<'tcx> {
  12     pub fn new(ty: Ty<'tcx>) -> Self {
  13         ImpliedOutlivesBounds { ty }
  14     }
  15 }
  16
  17 impl<'tcx> super::QueryTypeOp<'tcx> for ImpliedOutlivesBounds<'tcx> {
  18     type QueryResponse = Vec<OutlivesBound<'tcx>>;
  19
  20     fn try_fast_path(
  21         _tcx: TyCtxt<'tcx>,
  22         _key: &ParamEnvAnd<'tcx, Self>,
  23     ) -> Option<Self::QueryResponse> {
  24         None
  25     }
  26
  27     fn perform_query(
  28         tcx: TyCtxt<'tcx>,
  29         canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Self>>,
  30     ) -> Fallible<CanonicalizedQueryResponse<'tcx, Self::QueryResponse>> {
  31         // FIXME this `unchecked_map` is only necessary because the
  32         // query is defined as taking a `ParamEnvAnd<Ty>`; it should
  33         // take a `ImpliedOutlivesBounds` instead
  34         let canonicalized = canonicalized.unchecked_map(|ParamEnvAnd { param_env, value }| {
  35             let ImpliedOutlivesBounds { ty } = value;
  36             param_env.and(ty)
  37         });
  38
  39         tcx.implied_outlives_bounds(canonicalized)
  40     }
  41 }